Electric burglar-alarm for vaults, safes, or the like.



B. SERAGNOLI. ELEGTRIC BURGLAR ALARM FOR VAULTS, SAPES, OR THE LIKE.

APPLICATION FILED OOT,14, 1908.

Patented Feb. 15, 1910.

UNITED sTA'rn rATENT OFFICE.

ENRICO SERAGNOLI, OF ARENZANO, ITALY.

ELECTRIC BURGLAR-ALARM FOR VAULTS, SAFES, OR THE LIKE.

To all whom it may concern:

Be it known that I, ENRIGO SERAGNOLT, a subject of the King of Italy,residing at Arenzano, Province of Genoa, Italy, have invented new anduseful Improvements in Electric Burglar-Alarms for Vaults, Safes, or theLike, of which the following is a specification.

This invention relates to that class of alarm systems, wherein theobjects to be protected are surrounded by envelops, preferably made ofmetal and wherein said envelops are filled with a gaseous fluid of apressure varying from the atmospheric pressure. It is customary in thesesystems to connect said envelops pneumatically with some contrivancewhich is adapted to close an electric alarm circuit when the pressure inthe envelop is subjected to a change. It is obvious that by this meansan effective protection of the objects is obtained as it is impossibleto get at said objects without disturbing the equilibrium of the gas insaid envelop.

For the purpose of improving the safety of the entire device it iscustomary to place the wires or portions of the wires of the alarmcircuit in pipes which are pneumatically connected with the envelop andwhich for this purpose are made of thin metal, so that any attempt todisturb said alarm circuit will also require a breaking of those pipesand cause a disturbance of the equilibrium of the gas.

An object of this invention is to provide an arrangement for theconductors in the aforementioned pipes according to which a connectionbetween the conductor and the pipe is obtained as soon as said pipe iscrushed inwardly to a certain extent.

In the drawing a pipe with a plurality of branch pipes is shown in whichconductors are disposed. One branch of the alarm circuit is formed bythe conductors 13, 1 1 and 15 in the pipes, while the other branch ofthe alarm circuit is connected to the pipe 17 or the branches extendingtherefrom. It is evident to any expert skilled in the art that thiscircuit would be closed when any of the conductors would come in contactwith the pipe. For the purpose of maintaining the conductors out ofcontact with the metallic conduits 16, 17 they must be insulatedtherefrom; It is obvious that the alarm circuit would not be closedbetween Specification of Letters Patent.

Application filed October 14, 1908.

Patented Feb. 15, 1910.

Serial No. 457,718.

the conductors and the conduit, under crushing of the conduit when saidconductors would be surrounded by customary insulation. In thisinvention therefore the conductor or one of the conductors is bare andto protect it against contact with the metal conduit the insulation isaccomplished by surrounding the same with a helically wound insulatingmember 18. The windings of said member are of a sufiiciently large pitchto leave relatively large portions of the conductor uncovered, so thatsaid conductor is adapted to contact with the wall of the conduit whenthe same is crushed. When two or more conductors are disposed in thepipe, the insulating member may be replaced by a conductor insulated inthe customary way by a coating of fabric or rubber or such like, saidinsulated conductor being wound about the bare conductor spirally andalso leaving relatively large portions of the bare conductor uncovered.This is indicated in the part 16 of the conduit. In the portion 17 ofthe conduit a plurality of insulated conductors and one bare conductorare helically intertwisted leaving relatively large portions of the bareconductor uncovered, so that said bare conductor may contact with thewall of the conduit when the latter is crushed in.

It is obvious that by the means described under normal conditions theconductors are prevented from contact with the wall and that the alarmcircuit is only closed when the conduit is crushed. By way of example analarm circuit is shown comprising a plurality of conductors branched offor extended from the conductors in the various pipes and leading to someform of indicating signal apparatus 19, which in itself is very wellknown and does not form the subject-matter of this invention. The sourceof the current is indicated with 20, while an alarm bell, indicated by21 is connected to the conduit by a wire 22. It is obvious that thearrangement of this alarm circuit may be subject to various changes.

I claim 1. In an electro-pneumatic alarm system the combination of athin metal conduit, a bare conductor within said conduit, an insulatingmember helically surrounding said conductor leaving relatively largeportions of the same uncovered, said conductor being adapted to contactwith the wall of said conthe wall of said conduit, when the same iscrushed and an alarm circuit including said conductor and said conduit.

In testimony whereof I have signed my name to this specification in thepresence of 15 two witnesses.

ENRIGO SERAGNOLI. lVitnesses C. A. FERRAR,

Fro RINALDINI.

